The realization of effective social media recommendation systems, as reviewed in [1]}, [2]}, presents several challenges that in recent years have brought drastic changes to the field. In particular, some of the biggest challenges are
the highly diverse information they process (e.g. content, trust, connections),
the complex dynamics of the interactions,
the fast pace of growth of the social graph,
and the enormous amount of multimedia and textual elements to process [3]}, [4]}.
In the case of the CWBRS, the size of the internal social network is limited (i.e. the number of students)
and a big part of the data will come preselected by the external RS, thus forming an implicit two stages approach [5]}, [4]}, [7]} that will reduce the computational burden.
However, the creation of a CWB-RS presents several other theoretical, technical and ethical challenges that are mostly not faced by classical RS.
